The invention relates generally to a torsional sensor used for measurement of at least one parameter of a fluid by the propagation of torsional wave energy along the torsional sensor located partially in contact with the fluid.
In industrial process control, it is often required to determine at least one parameter attributed to fluids along flow paths, for example in pipes. The parameters may include density of the fluid, fluid velocity, fluid level, temperature, fluid phase, or the like. There are a number of known sensors, which are used for detection of parameters associated with the fluids.
One such sensor used for detection of parameters associated with the fluids is a torsional sensor. In such a device, the torsional sensor is partially inserted into the fluid whose property needs to be measured. Wave energy is guided along the sensor held partially in contact with the fluid. The parameter of the fluid surrounding the torsional sensor influences the torsional wave characteristics, specifically the time of flight of the wave mode. In other words, the interaction of the guided wave energy along the sensor with the fluid results in a lower velocity of propagation of the guided wave energy along the sensor, so that the change in flight time of the wave, as compared to a reference time with the sensor in air or vacuum, provides an indication of a parameter of the fluid in contact with the sensor. In particular circumstances, where at least one of the fluid composition, container geometry and sensor characteristics are known, a measurement of flight time of the wave energy guided along the sensor may provide an indication of a parameter of the fluid. However, none of the known torsional sensor designs results in an improvement in measurement of at least one parameter through a longer time of flight for a given wave mode. Moreover, the known torsional sensor designs are not suitable for measurement of at least one parameter of different type of fluids, specifically, one phase fluid, two-phase fluid mixture, and multi-phase fluid mixture.
As a result, there is a continued need for an improved torsional sensor that addresses at least one of these and other shortcomings.